Inheritance of Aroma in Six Rice Cultivars

Abstract

‘Jasmine 85’, a soft‐cooking aromatic rice (Oryza sativa L.) cultivar, was released in the USA with the objective of displacing imported Thai Jasmine rice in local markets. However, the reduced aroma and off‐white color of its milled rice limit its marketability. The present objective was to determine the number of genes controlling aroma in four rice lines (Jasmine 85, ‘Amber’, a dwarf mutant from ‘Basmati 370’ (PI 457917), and ‘Dragon Eyeball 100’), and to evaluate the allelism of aroma in these four lines and with the single recessive gene known to be in both ‘A‐301’ and Della‐X2. Lack of leaf aroma in aromatic/non‐aromatic F1 hybrids indicated the recessive nature of the aroma in all studied rices. F2 segregation ratios revealed that Jasmine 85 and PI 457917 each contain a single gene for aroma, and the aromatic nature of the F1 leaves from crosses with each other and with A‐301 and Della‐X2 revealed that the aroma genes in all four cultivars are allelic. Amber and Dragon Eyeball 100 each contain two aroma genes, a novel gene plus one allelic to the gene in A‐301, Della‐X2, Jasmine 85, and PI 457917. Incorporation of a novel aroma gene into Jasmine 85 could potentially increase its marketability. No linkage was detected between the two aroma genes in Dragon Eyeball 100 and five morphological characters. High levels of sterility observed in Amber F2 populations may hinder the use of its novel aroma gene.